In many cases, a vehicle such as a hybrid car or an electric car is provided with a current detection device for detecting a current flowing to a bus bar connected to a battery. Moreover, in some cases, a current detection device of a magnetic proportion type or a current detection device of a magnetic balance type is employed as the current detection device.
The current detection device of the magnetic proportion type or the magnetic balance type includes a magnetic material core and a magneto-electric converting element as described in Patent Documents 1, 2, and 3, for example. The magnetic material core is a substantially ring-shaped magnetic body that has both ends opposed to each other across a gap portion and is continuously formed around a hollow portion through which a bus bar penetrates. The hollow portion of the magnetic body is a space through which a current to be detected passes (space for detecting current).
Furthermore, the magneto-electric converting element is disposed in the gap portion of the magnetic material core, and detects a magnetic flux which is varied depending on a current flowing through the bus bar provided to penetrate through the hollow portion and outputs a detecting signal of the magnetic flux as an electric signal. For the magneto-electric converting element, a Hall element is usually employed.